The present disclosure relates to electronic devices connectable to a host computer through a universal serial bus (USB).
In recent years, universal serial buses (USBs) have been used to connect a host computer (hereinafter, may be referred to as a USB host) such as a personal computer (PC) to peripheral devices (hereinafter, may be referred to as USB devices) such as a mouse, keyboard, scanner, and printer.
In recent years, not only host computers, but also an increasing number of peripheral devices have been provided with a power saving mode of operating on low power for reduced power consumption.
A peripheral device connected to a host computer through a USB receives a status request issued by the host computer at a fixed time interval. In response to the status request, the peripheral device needs to issue a response indicating the status of the peripheral device. Therefore, the peripheral device cannot stay continuously in the power saving mode for a long time.
The following describes one example of a system that solves the above problem and allows peripheral devices to stay continuously in power saving mode for a long time. In the system, when a printer is in a status switchable to the power saving mode, the printer informs a host computer about the switchable status. In response, the host computer suspends a specific USB thereof to which the printer is connected. Thus, the host computer transmits no further status request to the printer.
While the USB port is suspended, the printer connected to the USB port receives no further status request from the host computer. This allows the printer to stay continuously in the power saving mode for a long time.